Process for treating tanning substances soluble with difficulty contained in crude quebracho liquors.



35 stance.

50 The treating of v STATES PATENT o FIcEQ "HANS FRANKIE, WILSDORF, NEAR BODENBACH, AUSTRIA, ASSIGNOR OF NINETY ONE-HUNDREDTH S TO ALBERT REDLICK, VIENNA, AUSTRIA.

rnoonss FOR 'mrm'rmo ramrfiw'suns/muons SOLUBLE WITH DIrrIcUL'rY CONTAINED IN CRUDE QUEBRACHO LIQUOBS.

No Drawing] Austria, have invented certain new and useful Improvements in Processes for Treating Tanning Substances Soluble with Difiiculty Contained in Crude Quebracho Liquors, of which the following is a specification.

According'to U. S. Letters--.Patent, No.

939,742, granted November 9, 1909, quebracho extracts solublev in the cold, can be obtained by heating non-treated quebracho liquors with a "'ven quantity of an alkali for a certain time, with exclusion of air,

with or without pressure, and after neutrali- .zation, separating by cooling the insoluble resin-like substances from the valuable portions soluble cold. The patent specification states that the tanning substances soluble with difliculty, which-are contained in "the non-treatedflquebracho liquors, are converted by this process into easily soluble tanning substances.

According to 'my observations, by cooling technical non-treated uebracho l1quors to complete clarification, a out 40% of the dry substance contained in the cloudy li uor, are precipitated in the form of insolu 1e subso stances. If however the liquors are first Y ,treated by the process described in-the patent above referred to, the subsequent cooling produces a separation of a much smaller quantity-about 20%of the total d sub- The. figures given are mere y aproximate, as t e composition of uebracho iquors as regards the proportion o tanning substances soluble with difiiculty, depends on the nature of the wood and onthe .work

40 of extraction.

earths (Mg, Ca, Sr, Ba) and subsequent Alkaline earths have howneutralization. ever a hi her efiiciency, so that the same result is o tained with considerably smaller quantities.

terial soluble with difiiculty, with asslstance of compounds of metals of alkaline earths has however another very important ad- Speciflcetion of Letters fatent.

Application filed TRIM-26,1914. SCI-1&1 N0. 847,514.

uebracho tanning ma- I Patented Oct. 2,1917.

vantage. It is possible to remove from the liquor the substances used for the treatment, 56

,difliculty or insoluble (for instance sulfate of barium, sulfate of strontium, oxalate of calcium, etc) In that'way, products of the degree of purity of non-treated extracts are by converting them into a salt soluble with obtained, which contain only a comparatively small proportion of sa which is of great advantage for tanning. Ii extracts richer in salts are used for tanning, the

proportion of tanning material to salt is quickly altered during tanning','and a liquor is soon produced which contains too much salt. in comparison to "the tanning material.

The high proportion of salt in strongly exhauste liquors produces a bad tanning, as

the hides decay in the same. Tanners con- 7 side'r such spent liquors as absolutely useless on account of the high proportion ofsalts, although they still contaln' a com paratively high proportion of tanning material. This drawback can be obviated by using extracts poor in salts. An extract obtained by the abovedescribed new process, is superior in that respect to that obtained by alkali treatment in accordance with the patent above mentioned. The removal of the salts formed in the new process, has moreover the advantage of enabling extracts tobe obtained with a correspondingly higher proportion of tanning material, which results in a savin of frelght.

The ingredients which cooling to 10-15C. In that way, liquors are obtained which, whatever their de ree of concentration, remain clear at the coo ing temperature, and consequently give after concentration an excellent extract soluble in the cold. With reference to the carrying out of'the process, it must be pointed out that hot llquorsstirred with oxids, hydroxids or salts are not rendered soluble by the process, can be separated by- (for instance carbonates) of alkaline earths to a porridge, are heated for a long time I with exclusion of air, in autoclaves, refer ably to about C. For one'hecto iter of liquor, it issufiicient to add about 10-15 gr. of caustic lime (CaQ) or approximately the equivalent quantity of another of the substances mentioned, After the reaction is completed, a quantity of acid (for instance acetic acid, hydrochloric acid, etc.) equivalent to the compound introduced,,isadded, or, if it is intended to obtain a liquor poor in salts, an acid which formswith the alkaline earth utilized, an insoluble salt or a salt soluble with difliculty, which is preferably removed from the liquor by hot filtration.

The insoluble substances thereby precipitated', can be separated from the soluble ones by subsequent coolingiand clarifying.

The de osit, the quantity of which, as stated, is a out contains of course varying quantities of easily soluble tanning ma- K terial or tanning material soluble with difiiculty which escaped the reaction, since it would be difiicul-t and tedious to consider'in' every single case the fluctuating proportion between easily soluble tanning materials and those soluble with difficulty, in order to cal-- 'culate accordingly in a more accurate manner the required quantities of the efiective known sulfiting and represent then a tancold.

substance. The greater portion of the tanning material soluble with difiiculty, can be converted into soluble form by-a further treatment. Insoluble substances resisting.

.my hand in presence of two subscribing this treatment, can be dissolved by the well ning material which, though it can be used, does not possess the eminent tanning properties, of the main portion soluble in the J aaaaeeo What I claim as m invention and desire to secure by Letters atent is 1. The process of treating crude-quebra- 'cho liquors containin diflicultlysoluble tanning substances, which comprises heating such liquor while air is excluded therefrom with an alkaline compound of alkaline earths of a character capable of "complete conversion by. a suitable acid into an insoluble salt; 40 neutraliain the liquor by adding thereto the require quantityof "acid, and separating the liquor fromthe insoluble residue.

2. The process of treating cnude quebracho liquors containing diflicultly soluble 4E- tanning substances, which comprlsesheating such liquor while air is excluded therefrom with .an alkaline compound of alkaline earths capable of complete conversion into an insoluble salt by a suitable acid, neutral izing such liquor "by adding thereto an acid of a character which will combine with said alkaline earths to form an insoluble salt, and separating such liquor from the insoluble residue. Q 1

In testimony whereof I have hereunto set witnesses. r

DR. HANS F-RANKE.

Witnesses LEO lBERoHoLz, PAUL Alums. 

